Three airlines have challenged the Transportation Department’s new price-advertising rule nefore the U.S. Supreme Court, claiming that the DOT is violating the First Amendment by prohibiting airlines from advertising base prices net of taxes and fees. The airlines also claim that the DOT has been violating the Airline Deregulation Act by imposing unique requirements such as “the size of typeface and the length of mandatory refunds — in an industry that Congress expressly chose to deregulate.”

The DOT’s price-advertising regulation for air travel was adopted in 2011 as part of a package of consumer protection initiatives and became effective in January. The new rule requires that advertised prices include all taxes and mandatory fees, regardless of their source.

A decision on whether the Supreme Court will take up the case is expected early next year.